Table 1.
Clinical goals for organs at risk to be satisfied by H&N plans. In difficult cases, the physician might allow the relaxation of a goal to the number observed in parenthesis. The achievable parotid gland mean dose constraint is estimated per patient using the heuristic proposed by Hunt et al.19 In addition to the structures in the table, hot spots more than ≈1 cm outside of the envelope of the lowest dose PTV are not allowed.
| Structure | Constraint |
|---|---|
| Cord | Dmax ⩽ 45 Gy (50 Gy) |
| Brainstem | Dmax ⩽ 50 Gy (60 Gy) |
| Chiasm | Dmax ⩽ 54 Gy (60 Gy) |
| Mandible excluding all PTVs | Dmax ⩽ 104% of low PTV Rx |
| Cochlea | Dmax ⩽ 50 Gy |
| Brachial plexus | Dmax ⩽ 65 Gy |
| Lens | Dmax ⩽ 5 Gy (10 Gy) |
| Eyes/retina | Dmax ⩽ 45 Gy |
| Optic nerve | Dmax ⩽ 54 Gy |
| Larynx | Dmean ⩽ 40 − 45 Gy |
| Parotid | Dmean ⩽ 26 Gy |
| Oral cavity | Dmean ⩽ 35 − 40 Gy |